1. Field of the Invention
This invention relates to a washer with an elastic water-swellable rubber which is used as a water sealing device when two segments are connected by a bolt at junctions thereof, or in similar cases.
2. Description of the Prior Art
Concrete segments are widely used for constructing architectural structures such as tunnel, etc. These concrete segments are gradually assembled in such a manner by being connected by a bolt at junctions and are serve as component elements for constructing such architectural structures as tunnels, etc.
Water sealing devices are often used together with a bolt in order to water seal the junctions when the concrete segments are connected by a bolt. As one example of a water sealing device used in such instance as just mentioned, there is a water sealing packing member disclosed in, for example, Japanese Utility Model Early Laid-open Publication No. Sho 62-133019. This water sealing packing member is used for water sealing the surrounding area of the bolt, and comprises a disc washer and an annular packing member axially aligned with each other and integrally formed by fitting the packing member into the washer or fixing them by adhesive. The Japanese Publication also discloses that the annular packing member is preferably formed of an elastic water-swellable composition.
However, where the conventional water sealing packing member is used as a water sealing device of concrete segments, there was such problems as that the washer used together with the water sealing packing member suffered from serious corrosion over the passage of years, because of the circumstances under which it is used are usually bad.
Moreover, there were such problems as that the water sealing function is not sufficient, because the integral connection between the washer and the water sealing packing member is not necessarily perfect.